I never heard of it either until fatfred posted about it. Apparently, my decision to use the ‘good’ silver for every day and my preference for ‘traditional’ brass door knobs has been keeping us healthier than I realized.
In case there is someone else out there who has never heard of this, from Wikipedia:
The oligodynamic effect (Greek: oligos = few, Greek: dynamis = force) was discovered in 1893 by the Swiss Karl Wilhelm von Nägeli as a toxic effect of metal ions on living cells, algae, molds, spores, fungi, viruses, prokaryotic and eukaryotic microorganisms, even in relatively low concentrations. This antimicrobial effect is shown by ions of mercury, silver, copper, iron, lead, zinc, bismuth, gold, aluminium, and other metals.
Brass doorknobs disinfect themselves in about eight hours, while stainless steel and aluminium knobs never do. Unvarnished brass doorknobs therefore tend to be more sanitary than stainless or aluminium doorknobs. Silver spoons (and other silverware) self-sanitize due to the oligodynamic effect.
So what I want to know is, if we’ve known about this effect since 1893, why aren’t brass and copper coatings on practically every public touch surface? Especially in medical buildings, but also grocery store cart handles, public sink taps and the like.